Rename {Core,TextEditor},{Base,}TextDocument classes

First step of some more 'Base' removal in TextEditor.
s/Core::TextDocument/Core::BaseTextDocument/
s/TextEditor::BaseTextDocument/TextEditor::TextDocument/

Change-Id: I71ba325a2f0ad72ec9dae0d96846cbae72d326f7
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/glsleditor/glslhighlighter.cpp

@@ -77,7 +77,7 @@ void GlslHighlighter::highlightBlock(const QString &text)
     lex.setScanKeywords(false);
     lex.setScanComments(true);
     const int variant = languageVariant(parent()
-                         ? static_cast<BaseTextDocument*>(parent())->mimeType()
+                         ? static_cast<TextDocument*>(parent())->mimeType()
                          : QString());
     lex.setVariant(variant);